The present invention relates to a new and distinctive Zantedeschia cultivar, designated 7033-01. The genus is restricted to the African continent with several species being recognized, including Z. aethiopica (Richardia Africana) referred to as the Common Calla; Z. aethiopica minor; Z. elliottiana and Z. angustiloba (R. Pentlandii) referred to as the Yellow Callas; Z. rehmannii referred to as the Pink Calla; Z. albo-maculata, the Spotted Calla and Z. melanoleuca, the Black-throated Calla.
These deciduous perennials are native to South Africa. They can be planted in a greenhouse that has a minimum temperature of 50° F. or outside where climates are mild. They are mainly grown for their attractive, large flower spathes, which are usually produced in the spring and summer. Calla Lilies or Arum Lilies, as they are commonly known, are grown in large quantities by commercial growers because they are commonly used for decoration at Easter, weddings, funerals and throughout the spring and early summer months.
The flower spathes of the common Zantedeschia are often white with a yellow spadix and it produces glossy, plain, arrow-shaped leaves. Some varieties grow 2 to 3 feet high. The spathes of the Yellow or Golden Callas, Z. elliottiana, are yellow with spotted leaves that are arrow or ovate-shaped. Z. rehmannli, the Pink Calla or Pink Arum, produces lavender-red, rose-red, violet-red or pink spathes and is a smaller plant (growing up to 16 inches) than the white or yellow flowered varieties. Its leaves are lanceolate and plain.
Zantedeschia are an excellent cut flower and last a long time in water. The striking Zantedeschia “flower” is actually many tiny flowers arranged in a complex spiral pattern on the central column (spadix). The tiny flowers are arranged in male and female zones on the spadix. The top portion of the spadix is male flowers and the lower part is female. If you look through a microscope, you may see the stringy pollen emerging from the male flowers which consist largely of anthers. The female flowers have an ovary with a short stalk above it, which is the style where the pollen is received. The spadix is surrounded by the white or colored spathe. It is believed that the whiteness of the spathe is not caused by pigmentation, but is an optical effect produced by numerous airspaces beneath the epidermis.
The Z. aethiopica flowers are faintly scented, which attracts various crawling insects and bees that are responsible for pollinating the flowers. Cross pollination occurs as the anthers of each flower ripen before the ovaries. A white crab spider of the family Thomisidae visits the flower to eat the insects. This spider does not spin webs and uses its whiteness as camouflage against the spathe. The spathe turns green after flowering and covers the ripening berries. It rots away when these are ripe and the succulent yellow berries attract birds, which are responsible for seed dispersal.
There are numerous steps in the development of any novel, desirable plant. Plant breeding begins with the analysis and definition of problems and weaknesses of the current germplasm, the establishment of program goals, and the definition of specific breeding objectives. The next step is selection of germplasm that possess the traits to meet the program goals. The goal is to combine in a single variety an improved combination of desirable traits from the parental germplasm. These important traits may include vigorous growth, height, color, disease, insect and virus tolerance.
Choice of breeding or selection methods depends on the mode of plant reproduction, the heritability of the trait(s) being improved, and the type of cultivar used commercially (e.g., F1 hybrid cultivar, pureline cultivar, etc.). For highly heritable traits, a choice of superior individual plants evaluated at a single location will be effective, whereas for traits with low heritability, selection should be based on mean values obtained from replicated evaluations of families of related plants.
The complexity of inheritance influences choice of the breeding method. Backcross breeding is used to transfer one or a few favorable genes for a highly heritable trait into a desirable cultivar. This approach has been used extensively for breeding disease-resistant cultivars. Various recurrent selection techniques are used to improve quantitatively inherited traits controlled by numerous genes. The use of recurrent selection in self-pollinating crops depends on the ease of pollination, the frequency of successful hybrids from each pollination, and the number of hybrid offspring from each successful cross.
Each breeding program should include a periodic, objective evaluation of the efficiency of the breeding procedure. Evaluation criteria vary depending on the goal and objectives, but should include gain from selection per year based on comparisons to an appropriate standard, overall value of the advanced breeding lines, and number of successful cultivars produced per unit of input (e.g., per year, per dollar expended, etc.).
Promising advanced breeding lines are thoroughly tested and compared to appropriate standards in environments representative of the commercial target area(s). The best lines are candidates for new commercial cultivars; those still deficient in a few traits may be used as parents to produce new populations for further selection.
These processes, which lead to the final step of marketing and distribution, usually take from six to 12 years from the time the first cross is made and may rely on the development of improved breeding lines as precursors. Therefore, development of new cultivars is a time-consuming process that requires precise forward planning, efficient use of resources, and a minimum of changes in direction.
A most difficult task is the identification of individuals that are genetically superior, because for most traits the true genotypic value is masked by other confounding plant traits or environmental factors. One method of identifying a superior plant is to observe its performance relative to other experimental plants and to a widely grown standard cultivar. If a single observation is inconclusive, replicated observations provide a better estimate of its genetic worth.
The goal of plant breeding is to develop new, unique and superior Zantedeschia cultivars and hybrids. The breeder may initially select and cross two or more parental lines, followed by self pollination and selection, producing many new genetic combinations. The breeder can theoretically generate billions of different genetic combinations via crossing, selfing and mutations. The breeder has no direct control at the cellular level. Therefore, two breeders will never develop the same line, or even very similar lines, having the same Zantedeschia traits.
Each year, the plant breeder selects the germplasm to advance to the next generation. This germplasm is grown under unique and different geographical, climatic and soil conditions, and further selections are then made, during and at the end of the growing season. The cultivars which are developed are unpredictable. This unpredictability is because the breeder's selection occurs in unique environments, with no control at the DNA level (using conventional breeding procedures), and with millions of different possible genetic combinations being generated. A breeder of ordinary skill in the art cannot predict the final resulting lines he develops, except possibly in a very gross and general fashion. The same breeder cannot produce the same cultivar twice by using the exact same original parents and the same selection techniques. This unpredictability results in the expenditure of large amounts of research monies to develop superior new Zantedeschia cultivars.
The development of new Zantedeschia cultivars requires the development and selection of Zantedeschia varieties, the crossing of these varieties and selection of superior hybrid crosses. The hybrid seed is produced by manual crosses between selected male-fertile parents or by using male sterility systems. These hybrids are selected for certain single gene traits such as vigorous growth, greater height, color, floriferousness, disease tolerance and pollen production which indicate that the seed is truly a hybrid. Additional data on parental lines, as well as the phenotype of the hybrid, influence the breeder's decision whether to continue with the specific hybrid cross.
Pedigree breeding and recurrent selection breeding methods are used to develop cultivars from breeding populations. Breeding programs combine desirable traits from two or more cultivars or various broad-based sources into breeding pools from which cultivars are developed by selfing and selection of desired phenotypes. The new cultivars are evaluated to determine which have commercial potential.
Mass and recurrent selections can be used to improve populations of either self- or cross-pollinating crops. A genetically variable population of heterozygous individuals is either identified or created by intercrossing several different parents. The best plants are selected based on individual superiority, outstanding progeny, or excellent combining ability. The selected plants are intercrossed to produce a new population in which further cycles of selection are continued.
Backcross breeding has been used to transfer genes for a simply inherited, highly heritable trait into a desirable homozygous cultivar or inbred line which is the recurrent parent. The source of the trait to be transferred is called the donor parent. The resulting plant is expected to have the attributes of the recurrent parent (e.g., cultivar) and the desirable trait transferred from the donor parent. After the initial cross, individuals possessing the phenotype of the donor parent are selected and repeatedly crossed (backcrossed) to the recurrent parent. The resulting plant is expected to have the attributes of the recurrent parent (e.g., cultivar) and the desirable trait transferred from the donor parent.
Descriptions of other breeding methods that are commonly used for different traits and crops can be found in one of several reference books (e.g., Allard, 1960; Simmonds, 1979; Sneep et al., 1979; Fehr, 1987).
Proper testing should detect any major faults and establish the level of superiority or improvement over current cultivars. In addition to showing superior performance, there must be a demand for a new cultivar that is compatible with industry standards or which creates a new market. The introduction of a new cultivar will incur additional costs to the seed producer, the grower, processor and consumer for special advertising and marketing, altered seed and commercial production practices, and new product utilization.